214 HYMENOPTERA OF AMERICA. [rART 1. 



knees, whitish ; anterior tibiae ferruginous or whitish ; 3d and 

 4th segments of the abdomen bordered with whitish beneath; 3d 

 finely edged above with this color. 



Bess. a. diff. — This Odynerus resembles the 0. Megsera in its 

 whitish ornaments, but it is smaller. Its smooth thorax, its rneso- 

 thorax without longitudinal grooves, its metathorax, smooth, 

 biangulate and without little teeth behind the post-scutel, its 

 immaculate front, and its transparent wings distinguish it super- 

 abundantly. 



The same characters distinguish it from the 0. foraminatus 

 and the 0. leucomelas. 



Hab. Lower California. I have received divers specimens ? 

 collected at Cape St. Lucas by Mr. John Xanthus and others from 

 Southern California (Berton). 



Observations. — This species has much of the form of the 0. 

 cubensis, but the male being unknown to me I place it with 

 hesitation in this division. If the male proves to have antenna? 

 terminated by a hook, the species will find its place in the Divi- 

 sion Ocbjiierus, next the 0. Alvaradi. With the 0. Erinnys it 

 is the only Pachodynerus yet known to inhabit the boreal 

 temperate zone. 



2d. Section. — Form more lengthened; thorax lengthened square 

 or retracted behind. Abdomen less conic, more cylindrical 

 or depressed. 



a. All the segments of the abdomen, except the first, bordered with yellow. 



SO. O. diabolidis Sacss. — Gracilis ; capite et thorace dense rugose 

 punctatis ; pronoti margine antico concavo, subcristato, angnlis sub- 

 acutis ; post-scutello truncato, transverse cristato-crenulato, metanoto 

 excavato, utrinque bispinoso, marginibus excavationis acutis vertica- 

 libus, supeme evanescentibus; abdomine subdepresso, antice rotundato- 

 truncato ; segmento satis elongate Oinniuo niger, abdominis seguientis 

 2-6 fiavo-ochraceo liinbatis ; tarsis apice fuscescentibns ; alis nebulosis. 



9 . Clypeo bicariuato, apice bidentato, vel acute biarjgulato. 



^ . Clypeo polygonali, apice truncato, luteo-argfntato ; labro, antennaruru 

 scapo subtus, macula frontali, fascia in sinu oculari, luteis. 



9 . Total lengtb, 12 mm. ; wing, 9.5 mm. 

 $ . Total length, 11 mm. ; wing. 7.5 mm. 



Odfn. diabolicus Sauss. Vespide*. I, 171, 60 (1552) ; III, 230.— Rev. 

 et Mag. de Zool. X, 1858, 167, 6. 



